a. Field of the Invention
This invention relates to a light scanning device. More particularly, it is concerned with an improvement in a light scanning device having a deflector which causes a light incidence position on the deflecting and reflecting surface thereof to shift in accordance with its deflecting action.
B. Description of the Prior Art
The deflector which causes a light incidence position on the deflecting and reflecting surface thereof to shift in accordance with its deflecting action is represented by a rotatory polygonal mirror.
Since this deflector causes the light incidence position on the deflecting and reflecting surface thereof to shift by the deflecting action thereof, when the light incidence position reaches the boundary part of the reflecting surface (hereinafter referred to simply as "corner part"), the incident light beam is irregularly scattered at the corner part thereof. On account of this, such type of deflector is disadvantageous in that, when it is applied to the so-called "laser beam printer," wherein a write-in light beam is shifted on a photosensitive material by the deflector to record informations therein, the photosensitive material is inevitably sensitized by the light scattered at this corner part.